Method for dimensioning graphical objects displayed on a display device

ABSTRACT

This document describes a method for creating a dimensioning object for at least one data object, wherein both the dimensioning object and the data object are displayable on a display device as graphical objects, wherein the method comprises the following steps:  
     a) applying dimensioning rules, which have been pre-defined for the data object, for determining a dimensioning object for the data object,  
     b) displaying the dimensioning object for the data object to be dimensioned on the display device, the dimensioning object being determined by means of the dimensioning rules,  
     c) storing the dimensioning object with the data object.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention concerns a method for the dimensioning ofengineering drawings, which are preferably created using a CAD program.

[0003] 2. Description of Related Art

[0004] Computers are increasingly used for the creation of engineeringdrawings. A computer typically comprises two display devices, namely ascreen and a printer, a keyboard having about 100 keys, two drives forremovable memory mediums, and a mouse, which can be used for moving apointing means (cursor) on the display screen. Typically, the computerfurther comprises a working memory, a non-volatile mass memory, and aprocessor. Special peripheral devices for the creation of engineeringdrawings are a tablet in connection with a pen for entering commands anddrawing elements like lines or circles. Often computers are connected toa network for exchanging data with other computers.

[0005] A multitude of programs is available for the computer aidedcreation of engineering drawings. Simple programs require that each lineand each dimension figure is entered individually. Many programs permitto combine lines to form an area and to provide the area with ahatching.

[0006] A large part of the time used for creating an engineering drawingis taken up by the dimensionings. A dimensioning comprises a dimensionfigure, a dimension line, and one or two auxiliary lines. Consequently atotal of three to four elements must be entered. Two points must bedefined for entering one line. Because of this, six points must beentered by the user for entering two auxiliary lines and one dimensionline for creating one dimensioning. It is time-consuming and thus notuser-friendly that the two points defining the dimension line must belocated on one auxiliary line each. Therefore the user has to positionthe pointing means very exactly before entering these two points.

[0007] Some CAD programs therefore support the user in the creation ofdimensionings by not requiring him to enter each element of thedimensioning individually. Before a dimensioning is created, it is laiddown as an option in the CAD program whether the dimension and auxiliarylines are to run horizontally, vertically or diagonally. For enteringone dimensioning the user has to define two points, which are to bedimensioned, using a pointing means, which may, for example, be movedusing a mouse. The auxiliary lines run through these points.Furthermore, the user defines a third point using the pointing means,the dimension line running through this point. The dimension figure isdetermined automatically by the CAD program on the basis of the distanceof the two auxiliary lines, and it is entered into the drawing at thedimension line. Consequently, in order to enter a dimensioning, the usernow only has to define three points, preferably by clicking thereon, foreach dimensioning.

[0008] When a dimensioning is entered in a direct, computer aided way,the dimension line is defined by entering one point only. The positionof this point in the direction perpendicular to the auxiliary lines doesnot influence the position of the dimension line. The position of thispoint parallel to the auxiliary lines at most has an aestheticsignificance. The point, which defines the dimension line, thereforedoes not have to be entered exactly, but only approximately. An onlyapproximate positioning of the pointing means by the user can be donemore quickly and therefore is more user-friendly.

[0009] However, there is still the disadvantage associated with theentering of dimensionings that the two points, which define theauxiliary lines, must be positioned exactly with respect to the bodyedges. Some CAD programs therefore have some snap-in grid, which can beactivated, or a so-called capture function. When the snap-in grid orcapture function is activated, the pointing means is moved during theentering process, i.e., for example, the mouse click, onto the linealready entered. Because of this, the user again has the advantage thathe only needs to position the pointing means approximately.

[0010] For entering drawing elements like, for example, lines, typicallymore data are required than are in fact entered. Typically only thestart and end points are entered for a line. Further data like, forexample, the line width, color and end points are stored as options inthe program before entering the line and are then available for enteringa plurality of lines. Options therefore are program settings, which arevalid for a plurality of inputs and can be changed either before orafter inputs.

[0011] As a rule, a plurality of drawing elements like, for example, aline, a circle or a text, are displayed on the screen completely or inpart. A data structure on the working memory corresponds to each of theelements displayed on the screen. Following the method of objectoriented programming, data structures are also called data objects. Inthis application only data objects are of interest which can bedisplayed on the screen as graphical objects. Normally only a smallnumber of the data objects stored on the working memory are displayed asgraphical objects because of the small dimensions of the screen.Therefore the terms “data object” and “graphical object” can often beused as synonyms.

[0012] Many CAD programs allow to combine a plurality of elements of adrawing in a group. The group then behaves like an element. All elementsof a group can, for example, be moved, copied or deleted jointly. Sincegroups behave like elements, they can be joined with further groups orelements to even more extensive groups. Groups and elements are bothcalled objects.

[0013] More often than not, a drawing is composed of a plurality ofgraphical objects. One or more drawings are located on a sheet. Aplurality of sheets form a folder or a project. Most CAD programs followthis division.

SUMMARY OF THE INVENTION

[0014] The object of the present invention is to provide a method bywhich a dimensioning can be added to data objects defining anengineering drawing in an easy way. This object is accomplished by thesubject-matter of patent claim 1. The dependent claims concern preferredembodiments of the present invention.

[0015] The dimensioning object according to the invention preferablycomprises a plurality of data objects like, for example, auxiliary ordimension lines. It is created automatically on the basis ofdimensioning rules. The user may influence the direction of dimensioningand the distance of the dimension lines from the data objects bypositioning the pointing means. Before creating the dimensioning object,the user may select data objects by dragging the mouse, whereby apreferably rectangular region is defined on the display device. All dataobjects are selected whose graphical representation is locatedcompletely inside the rectangular region. Furthermore the user mayinfluence the dimensioning object by selecting different dimensioningstyles.

[0016] The points to be dimensioned are preferably determined in atwo-stage process. In the first stage the contours of the data objectsare analyzed, and the contour points are determined. In the second stagethe points to be dimensioned are determined from the contour points. Theuser may influence the points to be dimensioned in the first stage byselecting the data objects and, in particular, in the second stage bymoving the pointing means. After the points to be dimensioned aredetermined, a preliminary dimensioning is generated and displayed. Thepreliminary dimensioning preferably only comprises part of the finaldimensioning object. On the basis of a change of position of thepointing means, the points to be dimensioned and a preliminarydimensioning are determined from the contour points again and again,such that the user may influence the preliminary dimensioninginteractively. If the user accepts the dimensioning, the dimensioningobject is stored together with the other data objects of the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] A preferred embodiment of the present invention will be explainedin more detail in the following, referring to the enclosed drawings. Inthis respect, the drawings show:

[0018]FIG. 1 is a flow chart depicting the method of the invention forthe dimensioning of engineering drawings,

[0019]FIG. 2 is a decision diagram further explaining the selection ofthe contour points, i.e. the possible points to be dimensioned,

[0020]FIG. 3A illustrates dimensioning of an L-shaped object independence of the position of the pointing means (cursor),

[0021]FIG. 3B illustrates dimensioning of the L-shaped object aftermoving the pointing means (cursor),

[0022]FIG. 4 illustrates a limited dimensioning of the L-shaped objectin dependence of the position of the pointing means (cursor), and

[0023]FIG. 5 illustrates a selection menu for different dimensioningstyles like linear dimensioning, ordinate dimensioning, symmetrydimensioning or dimensioning of a shaft in one or more axes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024]FIG. 1 shows a preferred embodiment of the method of theinvention. The flow chart in FIG. 1 has three starting points 2, 6 and10. This is intended to indicate that either one of the first two methodsteps 4 and 8 or both first method steps may be jumped over. The firstmethod step 4 “select new dimensioning style” is explained in moredetail below with reference to FIG. 5. Also method step 8 “selection ofthe graphical objects to be dimensioned” will be discussed below.

[0025] In method step 12 “determine contour points”, the contour of thegraphical objects to be dimensioned is analyzed. The possible points tobe dimensioned, from which the points that are in fact to be dimensionedwill be determined in method step 16, are called contour points. It willbe explained in more detail in connection with FIG. 2 how the contourpoints are determined. The user may influence the dimensioning using apointing means in method step 14 “take cursor position and movement intoaccount when determining the dimensioning”. A cursor, which is movableusing a mouse, may be employed as a pointing means. Alternatively, thecursor may also be moved using a tablet in connection with a pen. It isfurther explained with reference to FIGS. 3A, 3B and 4 how the user mayinfluence the dimensioning using the pointing means.

[0026] In method step 16, a sub-selection is made from the contourpoints determined in method step 12, and thus the points actually to bedimensioned are determined. That is to say, if several contour pointsare located on an auxiliary line, they should not be dimensioned severaltimes. If two contour points are located on an auxiliary line, and ifthese are connected by a body line, then only the point closer to thedimension line will be dimensioned. Unnecessarily long auxiliary linesare avoided by this measure. If the two contour points are not connectedby a line like, for example, the central points of two circles, then thepoint farther away from the dimension line will be dimensioned. Therebythe two points are connected by the auxiliary line. Thus the engineeringdrawing clearly shows that one dimension is valid for both points.

[0027] In principle the contour analysis of method step 12 could alsotake place in method step 16, such that the points to be actuallydimensioned are determined directly from the contour analysis. Sincemethod steps 14, 16, 18, 20 and 22 are executed cyclically, these methodsteps should comprise as few computing operations as possible. Therebythe execution of these method steps will be accelerated, and the displaydevice reacts more quickly to the movement of the pointing means.Therefore the contour analysis in method step 12 for determining thecontour points is not executed cyclically in the preferred embodiment ofFIG. 1.

[0028] After the points to be actually dimensioned have been determinedin method step 16, a “preliminary dimensioning using dimensioning rules”is determined in method step 18. In method step 20 the preliminarydimensioning is displayed. The preliminary dimensioning on the one handshall provide the user with an idea of the appearance of the finaldimensioning as accurately as possible, and on the other hand itscreation again shall need as little computing power as possible. Therebythe cycle time of the steps executed cyclically is held as short aspossible. If the dimensioning only comprises a few graphical objects anda powerful computer is available, then the preliminary dimensioning maycomprise all elements of the final dimensioning. If the computing timefor creating the preliminary dimensioning increases, then preferably thedimension figures are omitted first. The arrowheads of the dimensionlines will not be calculated and displayed for reducing the computingtime even further. Furthermore the preliminary dimensioning may compriseonly part of the auxiliary and/or dimension lines.

[0029] If several application programs happen to run on a computer atthe same time, then no application should put an unnecessary load on thecomputer system in order not to slow down the other applicationsunnecessarily. This is the objective of method step 22. As long as thepointing means is not moved, it is not necessary to execute method steps14, 16, 18 and 20 and to display the same preliminary dimensioning againand again.

[0030] It is checked in method step 24 whether the user agrees with thepreliminary dimensioning. If the user changes the position of thepointing means, then he obviously is not yet satisfied with thepreliminary dimensioning. Therefore a further preliminary dimensioningis generated in method steps 14, 16, 18 and 20. If the user finallyagrees with the final dimensioning indicated by the preliminarydimensioning, he indicates this to the computer. Preferably this takesplace by pressing a key or a combination of keys, in particular bypressing the return key.

[0031] In order to be able to distinguish the preliminary dimensioningand the final dimensioning, the former is preferably displayed in adifferent gray scale level or in a different color (see FIG. 3A, FIG.3B). In this way the user always sees whether he can still change thepreliminary dimensioning by moving the pointing means, this is to saywhether the method is in step 20 or 22 or whether the method has alreadybeen finished.

[0032] According to another preferred embodiment, the method steps 18and 20 are combined such that each dimensioning element to be drawn,like, for example, a dimension or auxiliary line, is immediatelydisplayed on the display device even before a further dimensioningelement is calculated. If the user moves the pointing means, methodsteps 18 and 20 are aborted and the method is continued at step 14.Since dimension and auxiliary lines are calculated and displayed first,then arrowheads and finally dimensions, the user can determine quicklywhether or not the dimensioning will conform to his expectations and caninfluence the preliminary dimensioning by moving the pointing means.

[0033] Now the determination of the contour points in method step 12will be explained in more detail with reference to FIG. 2. It hasalready been mentioned above that data objects may be grouped. Also theselection of the graphical objects to be dimensioned in method step 8may be considered as a data object group. The method in FIG. 2 has to beapplied to each data object selected in method step 8. If a data objectin the selection is a data object group, then the method of FIG. 2 isapplied in turn to all data objects of this group. In the end the methodshown in FIG. 2 is applied to all data objects which directly orindirectly via data object groups belong to the selection.

[0034] In FIG. 2 it is first distinguished whether the data objectrepresents a “body edge”, a “hidden edge”, a “symmetry line” or a“special object”. If the data object is a “body edge”, it is furtherdistinguished whether the data object is a “body line”, a “circle arc”or a “circle”. For “body lines” all corners are counted as contourpoints. In the preferred embodiment, however, corners which border onchamfers will not be dimensioned and therefore also not added to thecontour points. In another preferred embodiment also corners whichborder on chamfers will be added to the possible points to bedimensioned. The corresponding dimension line is labeled in thispreferred embodiment not only with the depth of the chamfer, but alsowith the associated angle.

[0035] If a “body edge” represents a “circle arc”, the end points of the“circle arc” are considered as contour points. If the “circle arc”borders on two “body lines”, which delimit an angle larger than 60°,then the intersection point of the two adjoining “body lines” is furtherconsidered as a contour point. For “body edges” which form “circles”,the central point is added to the contour points.

[0036] If the data object is not a “body edge”, it is tested whether ornot the data object is a “hidden edge”. In the preferred embodiment ofthe present invention it is stored as an option whether or not “hiddenedges” will be processed as “body edges”. The change of options takesplace by methods which can be performed independently of the method ofthe invention in FIG. 1.

[0037] If the data object is not a “hidden edge”, it is tested whetheror not the data object is a “symmetry line”. For “symmetry lines” theend points are added to the possible points to be dimensioned. However,“symmetry lines” are only dimensioned in fact if they run in parallelwith the direction of dimensioning. Since the direction of dimensioningdepends on the position of the pointing means, it can only be determinedin step 16 whether or not the “symmetry line” will actually bedimensioned.

[0038] If the data object is not a “symmetry line” either, it is testedwhether or not the data object is a special object. The category“special object” mainly serves as an linking point for extensions of thedecision structure shown in FIG. 2. Special objects themselves havemethods which are able to inform the methods of the invention shown inFIG. 1 which points are to be added to the contour points. Screws, nutsand threads are named here as examples for special objects to bedimensioned.

[0039] Data object groups can also be considered as special objects. Inthis case the method which communicates the contour points to the methodof the invention of FIG. 1 can be described by the fact that the methodof FIG. 2 is applied to all data objects belonging to the group.

[0040] If the data object is not a “special object” either, it must be adata object which will not be dimensioned. Examples for such objects areauxiliary lines, dimension lines, tolerances and text.

[0041] The decision diagram shown in FIG. 2 serves for an easierunderstanding of the present invention and not necessarily depicts theunderlying programming. If the method of the invention is to beimplemented in an object oriented programming environment, a parentclass “CDataObject” would be defined. The parent class “CDataObject”comprises, among others, the methods “Draw” and “Points”. The method“Draw” displays the class “CDataObject” on the display device. Themethod “Points” determines all contour points of the data object. Themethods “Draw” and “Points” are preferably defined as virtual ones.Child classes “CBodyLine”, “CCircleArc”, “CCircle” and so on are derivedfrom the parent class “CDataObject”. The child classes also comprise themethods “Draw” and “Points”. Since each class and therefore each object(instance) now has the method “Points”, the selection in the decisiondiagram in FIG. 2 regarding the graphical object which represents thedata object is no longer necessary.

[0042] This selection can also be avoided in a programming environmentwhich only supports structured programming. In contrast to classes,structures cannot comprise methods. This disadvantage, however, isalleviated by the fact that structures may comprise pointers to methods.For the data objects “body line”, “circle arc”, “circle” and so on, thestructures “SBodyLine”, “SCircleArc”, “SCircle” and so on are defined.Further the methods “BodyLinePoint”, “CircleArcPoint”, “CirclePoint” andso on are defined, which for each data structure determine thecorresponding contour points. Each method expects a pointer to thecorresponding data structure as an input for determining the possiblepoints to be dimensioned. Vice versa, each data structure comprises apointer to the corresponding method in order to render the selection ofthe correct method superfluous.

[0043]FIGS. 3A, 3B and 4 explain the influence of the position of thepointing means with respect to the object to be dimensioned. Besides theposition of the pointing means, its velocity on the display device mayinfluence the dimensioning. Whether or not position and/or velocity ofthe pointing means have an influence, and which kind of influence theyhave, is stored as an option. In FIG. 3A the position of the pointingmeans (cursor) with respect to the L-shaped object to be dimensionedfirst determines the dimensioning direction, wherein in the preferredembodiment only four dimensioning directions are available during thefirst execution of method step 14: horizontally to the left,horizontally to the right, vertically up and vertically down. Withrespect to FIG. 3A, this means that the auxiliary lines horizontally runto the right from the object to be dimensioned. In FIG. 3A the auxiliaryline closest to the pointing means is determined as starting point ofthe dimension lines. Finally the pointing means also determines thedistance of the dimension lines from the drawing to be dimensionedwithin the framework of applicable standards.

[0044] In another embodiment a vector from a well-defined point of thedrawing to be dimensioned to the pointing means could determine thedirection of dimensioning, i.e. the direction of the auxiliary lines.Preferably the area's center of gravity could be used as well-definedpoint of the drawing to be dimensioned.

[0045]FIG. 3B shows the influence of a downward movement of the pointingmeans on the dimensioning. Because of the movement of the pointingmeans, the direction of dimensioning changes from “horizontally to theright” to “towards bottom right”. Here, the starting point of thedimensioning remains unchanged in the preferred embodiment. The distanceof the dimension lines from the graphical objects to be dimensioned canbe changed by changing the position of the pointing means only withinthe limits set by the applicable standards. In FIG. 3B the symmetrycross, which is located in the upwards pointing leg of the object to bedimensioned, will not be dimensioned since the horizontal symmetry lineis no longer parallel to the direction of dimensioning.

[0046] The position of the pointing means may further be used forinfluencing the selection of the graphical objects to be dimensioned inmethod step 8, if the corresponding choice of options is made or certainkeys are pressed at the same time. In FIG. 4, for example, only thosepoints are dimensioned which are located above the auxiliary line whichdefines the starting point of the dimensioning. Certain contour pointsare excluded from the dimensioning in method step 16, preferably bypressing one of the four cursor keys. Each cursor key selects one halfof the drawing with respect to the pointing means. The cursor key“upwards”, for example, selects the half plane above the pointing means.The number block may be used as an alternative to the cursor keys. Herethe numbers 2, 4, 6 and 8 have a functionality corresponding to that ofthe cursor keys. The numbers 1, 3, 7 and 9 select a quadrant. Forexample, the number 1 selects the quadrant to the left and above thepointing means. The selection of part of the contour points is canceledagain by pressing the number 5. In this manner the complete originalselection is dimensioned again.

[0047]FIG. 5 shows a menu with 19 different dimensioning styles forlinear dimensioning, ordinate dimensioning or symmetry dimensioning. Thedimensioning can be carried out either in horizontal or vertical or inhorizontal and vertical direction. A dimensioning style is selected byclicking the corresponding icon (switching region with picture) usingthe pointing means. The selected dimensioning style is preferablyindicated by coloring the top and the left margin of the icon and asmall square in the lower left corner of the icon in a dark color.Furthermore, four dimensioning styles for dimensioning of a shaft areshown in FIG. 5. After clicking an icon for a dimensioning style thedimensioning menu is closed.

[0048] The selection of the graphical objects to be dimensioned andthereby the selection of corresponding data objects in method step 8 cantake place in different ways. In the preferred embodiment the pointingmeans is dragged over the display while pressing a key at the same time,and thus a rectangle is defined. The positions of the pointing meanswhen the key is pressed and released define two corners of a rectangle.All data objects that are situated completely inside the rectangle areselected. When data object groups are concerned, all data objectsbelonging to this group must be situated completely inside the definedrectangle.

[0049] By pressing another key the drawing next to the pointing means onthe display device is selected. Here, first that data object isdetermined which comprises a part being especially close to the pointingmeans. The drawing associated with this data object is dimensioned.

[0050] By running the pointing means so that it defines a closed areawhile a third key is held depressed, those data objects are selectedwhich are located completely inside the closed area. In case the path ofthe pointing means, which has been covered while the third key waspressed, happens not to be closed, the two points are connected at whichthe pointing means was situated when the third key was pressed andreleased, such that a closed area results.

[0051] In another preferred embodiment, all data objects are selectedwhich are located at least in part in the closed area. This is also sofor the rectangle defined by means of the first key and the pointingmeans.

[0052] By pressing a fourth key, all elements of the drawing sheet whichis at least partially displayed on the display device are selected. Thedrawings on all pages which belong to a folder or a project can beselected by pressing further keys.

[0053] The selection step in method step 8 can be modified by settingother options such that the selection takes place automatically. Thosedata objects of a drawing can be selected automatically which arelocated closest to the pointing means on the display screen.Furthermore, all drawings shown on the display device can be selectedautomatically. Further, all drawings of a sheet or all sheets of aproject can be selected automatically. If everything is selected, thisselection step may be interpreted in a way that it does not take place.

[0054] After the user has indicated his agreement with the preliminarydimensioning in method step 26, the final dimensioning is determined anddisplayed. The final dimensioning preferably consists of a plurality ofauxiliary lines, dimension lines and dimension figures. The dimensioningobject therefore is a data object group. The dimensioning object isfinally stored with the other objects of the sheet or project which ispresently displayed. The project currently processed in the CAD systemis preferably contained in the working memory. Only in response to aspecial command of the user the older version of the project is updatedin the non-volatile mass memory of the computer. In the case of anextensive object, only part of the data objects are loaded into theworking memory, the remaining ones, for example, are dislocated as atemporary file onto the mass memory. The temporary file permits to undochanges.

[0055] As an alternative, extensive projects may advantageously bemanaged with the help of data bases. Here a record of the data basepreferably contains a data object. If the memory space of a record ischangeable, a record may also comprise a data object group, i.e. severaldata objects. As an alternative, data object groups may also be formedby references to other data objects. It is not necessary that the database is located completely on a computer. If the computer is connectedto a network, the data objects of a project may be stored on severalcomputers in a distributed way and may be edited by several users at thesame time.

What is claimed is:
 1. A method for creating a dimensioning object forat least one data object, wherein both said dimensioning object and saiddata object are displayable on a display device as graphical objects,wherein said method comprises the following steps: a) applyingdimensioning rules, which have been pre-defined for said data object,for determining a dimensioning object for said data object, b)displaying said dimensioning object for said data object to bedimensioned on said display device, said dimensioning object beingdetermined by means of said dimensioning rules, c) storing saiddimensioning object with said data object.
 2. The method of claim 1,wherein a selection from all data objects is made before applying saiddimensioning rules, and that said dimensioning object only comprisesdimensionings for the selected data objects.
 3. The method of claim 2,wherein said selection of data objects is made using a pointing means,wherein only data objects may be selected which are also displayed onsaid display device at least in part.
 4. The method of claim 1, whereinthat said dimensioning object is stored with said data object asdifferent entries in a data base.
 5. The method of claim 1, wherein stepa) comprises the following sub-steps: a1) determining all contour pointsof said data object, a2) determining the points to be dimensioned forsaid data object.
 6. The method of claim 5, wherein steps a2) and b) arerepeated cyclically until a user input takes place.
 7. The method ofclaim 6, wherein said cyclical repetition is only resumed in response toa movement of the pointing means exceeding a threshold value withrespect to distance or speed.
 8. The method of claim 1, wherein saidpredefined dimensioning rules consider, besides said data object, alsothe position and/or the movement of a pointing means.
 9. The method ofclaim 8, wherein a representation of said pointing means on said displaydevice defines a dimensioning direction and the distance of thedimensioning from the object to be dimensioned by its relative positionwith respect to said graphical object.
 10. The method of claim 8,wherein said pointing means is a cursor, which preferably iscontrollable by a mouse device and preferably is a crosshair-shapedcursor.
 11. The method of claim 1, wherein, after said displaying ofsaid dimensioning object according to step b), a user input takesplaces, and in dependence of said user input said displayed dimensioningobject is either stored or said displayed dimensioning disappears fromsaid display device.
 12. The method of claim 1, wherein said displayingof said dimensioning object according to step b) shows a preliminarydimensioning and is completed to form a final dimensioning in responseto a user confirmation.
 13. The method of claim 1, wherein adimensioning style is selected from a plurality of dimensioning styles,wherein at least part of the selectable dimensioning styles are shown onsaid display device for selection.
 14. The method of claim 13, whereinsaid dimensioning styles comprise linear dimensioning, ordinatedimensioning, symmetry dimensioning and dimensioning of a shaft, andthat the dimensioning selectably takes place only in horizontal orvertical direction or both in horizontal and vertical direction.
 15. Themethod of claim 1, further comprising determining whether one or morepossible points to be dimensioned on the object to be dimensioned areassociated with one of the classes “body edge”, “symmetry line”, “hiddenedge” and “special object”.
 16. The method of claim 15, wherein, for asymmetry line, end points are added to the possible points to bedimensioned.
 17. The method of claim 15, wherein symmetry lines are onlydimensioned if they are parallel to the direction of dimensioning. 18.The method of claim 15, wherein a hidden edge is processed like a bodyedge, when selected correspondingly.
 19. The method of claim 15, whereina special object determines its possible points to be dimensioneditself.
 20. The method of claim 15, wherein a point which is locatedclosest to the dimensioning is selected from several possible points tobe dimensioned which would show the same dimension value.
 21. The methodof claim 15, wherein end points of radii are only dimensioned if thetangential direction in this point is parallel to the direction ofdimensioning.
 22. The method of claim 15, wherein chamfers are notdimensioned.
 23. A computer-implemented system for creating adimensioning object for at least one data object, wherein both saiddimensioning object and said data object are displayable as graphicalobjects on a display device coupled to the computer system, comprising:a) means, performed by the computer system, for applying dimensioningrules, which have been pre-defined for said data object, for determininga dimensioning object for said data object, b) means, performed by thecomputer system, for displaying said dimensioning object for said dataobject to be dimensioned on said display device, said dimensioningobject being determined by means of said dimensioning rules, c) means,performed by the computer system, for storing said dimensioning objectwith said data object.
 24. An article of manufacture embodyinginstructions that when executed by a computer cause the computer toperform a method for creating a dimensioning object for at least onedata object, wherein both said dimensioning object and said data objectare displayable on a display device as graphical objects, wherein saidmethod comprises the following steps: a) applying dimensioning rules,which have been pre-defined for said data object, for determining adimensioning object for said data object, b) displaying saiddimensioning object for said data object to be dimensioned on saiddisplay device, said dimensioning object being determined by means ofsaid dimensioning rules, c) storing said dimensioning object with saiddata object.